The broad, long term objective of our proposed research is to demonstrate that infrared tomographic microscopy (ITM) may be successfully applied to laser surgical procedures to provide the basic scientific knowledge and biomedical engineering data required to predict therapeutic outcome and specify the dosimetry required for irreversible photocoagulation of targeted subsurface chromophores. Our central hypothesis for the proposed research is that application of infrared tomographic microscopy (ITM) provides a successful approach for pre- treatment diagnosis and treatment planning in laser surgical procedures involving photocoagulation of subsurface blood vessels. Successful completion of the proposed research is expected to result in the development of a new tomographic microscopy technique that will provide a scientific approach to the selection of laser dosimetry on an individual patient basis. The specific aims of this proposal are to: 1. Using ITM, conduct clinical studies involving port wine stain (PWS) patients to identify and quantify the principal reasons for treatment failure and thereby develop a predictive approach to laser therapy allowing the attending physician to provide realistic pre-treatment counseling to patients and family members. 2. Demonstrate clinical application of ITM to provide the attending physician guidance regarding optimal laser dosimetry [therapeutic light dosage (D[PWS]) and pulse duration (t[P])] for PWS laser treatment on a site-to-site basis throughout an extended treatment protocol. 3. Develop and demonstrate application of thermal-wave ITM to determine the spatial distribution of volumetric heat generation rate (Q[PWS]) in deep (500-1000mu m) PWS vessels. Demonstrate a thermal-wave ITM measurement may be used to predict the degree of lesion blanching and predict optimal laser dosimetry for treatment of PWS. Studies to develop and demonstrate application of thermal-wave ITM for improved laser treatment of vascular lesions will be guided by studies at three levels involving: (1) the chick chorioallantoic membrane (CAM) model; (2) the chicken comb animal model; and (3) clinical trials involving PWS patients. Successful completion of the proposed studies will provide the basis for a new tomographic microscopy technique that can substantially improve laser therapy.